Use of Refinery Off Gas (ROG) As CO2 Emission Reduction and Natural Gas (NG) Savings in Hydrogen (H2) Production

Abstract: In recent years, the stricter regulations regarding the presence of pollutants in gasoline and diesel have significantly increased the consumption of hydrogen. This is due to a greater severity in the hydrotreatment processes where hydrogen plays a fundamental role, not only to reduce the amount of sulfur present to the desired values, but also to increase the duration of the run due to the effect of higher precision partial on the catalytic bed.

On the other hand, as each time more heavy crude is processed, this situation with hydrogen is aggravated, and since the use of aromatics as an octane booster of fuels is also restricted, they cause gasoline-reforming plants to have lowered their run with the consequent decrease of the hydrogen by-product.

Everything mentioned above makes hydrogen a critical and expensive input for Refineries.

Much has been explored in the field of hydrogen recovery from different streams in Refineries and Petrochemical complexes. Different techniques have been used with their advantages and disadvantages, highlighting the recovery using PSA, Membranes or cryogenic recovery.

Less has been explored the insertion of a stream of Refinery Off Gas (ROG) directly as primary or complementary feed to a Steam Methane Reforming (SMR).

In the present work, mainly it is explored how, in theory, to use the (ROG) in an SMR in order to recover the hydrogen contained in it and reform the remaining hydrocarbons. Possible difficulties offered by this technique and how to solve them are shown.

On the other hand, the main operating variables obtained experimentally, their evolution over time and the meaning of their variations are analyzed. Using natural gas (NG) and different ROG / NG ratios as feed to the SMR.

This technique is very attractive, due to the low cost of ROG compared to other raw materials. In addition, mainly a current is used that in the best of cases was sent as fuel to furnaces and boilers taking advantage only of its calorific power, and last was burned in the flare and the combustion gases were sent to the atmosphere.